ci: Enable caching

src/bin/plugins/lib/npmpublish.yml

@@ -29,9 +29,20 @@ jobs:
       # etherpad-lite has been moved outside of $GITHUB_WORKSPACE, so it is now
       # safe to clone this plugin's repo to $GITHUB_WORKSPACE.
       - uses: actions/checkout@v2
-      - uses: actions/setup-node@v1
+      # This is necessary for actions/setup-node because '..' can't be used in
+      # cache-dependency-path.
+      - name: Create ep_etherpad-lite symlink
+        run: |
+          mkdir -p node_modules
+          ln -s ../../etherpad-lite/src node_modules/ep_etherpad-lite
+      - uses: actions/setup-node@v2
         with:
           node-version: 12
+          cache: 'npm'
+          cache-dependency-path: |
+            node_modules/ep_etherpad-lite/package-lock.json
+            node_modules/ep_etherpad-lite/bin/doc/package-lock.json
+            package-lock.json
       # All of ep_etherpad-lite's devDependencies are installed because the
       # plugin might do `require('ep_etherpad-lite/node_modules/${devDep}')`.
       # Eventually it would be nice to create an ESLint plugin that prohibits
@@ -58,10 +69,11 @@ jobs:
       - uses: actions/checkout@v2
         with:
           fetch-depth: 0
-      - uses: actions/setup-node@v1
+      - uses: actions/setup-node@v2
         with:
           node-version: 12
           registry-url: https://registry.npmjs.org/
+          cache: 'npm'
       - name: Bump version (patch)
         run: |
           LATEST_TAG=$(git describe --tags --abbrev=0) || exit 1